The present invention relates generally to disc drive data storage devices. In particular the present invention relates without limitation to thermal performance of a power integrated circuit in a disc drive.
In disc drives, relatively large currents are provided to a drive motor that spins a disc pack, to a voice coil motor that positions a read/write head and to power supply busses in the disc drive. Each of these currents is typically regulated, at least in part, by using discrete power semiconductor devices in the disc drive.
These discrete power semiconductor devices collectively dissipate a large amount of heat in relation to the size and surface area of the disc drive housing. There are substantial temperature rises in disc drives, however the temperature rise in each power semiconductor device is different and difficult to predict because the power dissipated varies depending on the mounting and usage of the disc drive.
There is a desire to monitor the heat rise in approximate ten different power semiconductor devices in a disc drive, so that disc access speed can be curtailed when any one of the power semiconductor devices approaches its maximum reliable operating temperature. The number of temperature sensors needed to do this monitoring, however, is cost prohibitive.
There is a need to provide monitoring of multiple power semiconductor devices in a disc drive that is both economical and that monitors a large number of power semiconductor devices. Embodiments of the present invention address one of more of these and other problems, and offer advantages over the prior art.
In the illustrated embodiments, a disc drive comprises a drive motor mechanically coupled to a disc and a voice coil motor mechanically coupled to a read/write head on the disc. A power integrated circuit is electrically coupled to the drive motor and the voice coil motor. The power integrated circuit includes an integrated temperature sensor providing a temperature output representing a temperature of the power integrated circuit. A control circuit receives the temperature output and provides a voice coil motor control output to the power integrated circuit as a function of the temperature output.
In preferred embodiments, the temperature output is a continuous representation of the temperature and the voice coil motor control output has an access speed that is adjusted after completion of a current read/write cycle depending on the temperature.
These and various other features as well as advantages that characterize the present invention will be apparent upon reading of the following detailed description and review of the associated drawings.